Elevator



March 21, 1961 J. 0. LONG 2,975,868

ELEVATOR Filed NOV. 26, 1957 2 Sheets-Sheet 1 INVENTOR /0//// [0;

ATTORNEYS March 21, 1961 J. c. LONG 2, 75,868

ELEVATOR Filed Nov. 26, 1957 2 Sheets-Sheet 2 INVENTOR BY www ATTORNEYS United ELEVATOR John C. Long, 90 Broad St., Charleston, S.C.

Filed Nov. 26, 1957, Ser. No. 699,024

7 (Jlaims. (Cl. 187-18) This invention relates to elevators, and more particularly to elevators in which up and down movement is controlled by a specially controlled expansible and contractible mechanism frame.

Elevators in which up and down movement is controlled by expansible and contractible linkage assemblies are known and various arrangements have been proposed for actuating these assemblies, but all have had certain disadvantages and limitations. One of the most important objections has been that they are susceptible of becoming jammed, resulting in either a jerky or uneven movement or complete inoperativeness. Thus, in elevators otherwise capable of rapid up and down movement by way of their expansible and contractible link mechanism, it is usually necessary to actuate the linkage slowly in efforts to operate the elevator smoothly and prevent mechanical failures by jamming.

A primary object of this invention is thus to provide a reliable controlled expansion frame elevator assembly capable of smooth and rapid up and down movement.

Another object of this invention is to provide an elevator in which up and down movement is actuated by expansible and contractible linkage mechanism controlled by novel differential drive arrangements.

' Other objects and advantages of the invention will become apparent from the following detailed description and drawings in which:

Figure l is a generallyperspective view schematically illustrating details of the elevator of this invention and the drive control;

Figure 2 is a fragmentary view partly in section showing the cage guide structure;

Figure 3 is a top elevational view of the differential drive control arrangement shown in Figure l; and

Figure 4 is a side elevation of the differential actuating mechanism of Figure l, with parts shown in phantom lines for illustrating expansion and contraction of the mechanism frame by the differential drive arrangement which controls up and down movement.

Figure 1 shows an elevator assembly indicated generally at 1%) comprising a pair of spaced expansible and contractible mechanism frame assemblies 12 and 14 made from a series of pivotally connected levers, the lovers of each frame assembly 12 and 14 lying essentially in a ver tical plane. Mounted at the top of and between the mechanism assemblies 12 and 14 is an elevator load carrying cage, car or other platform 16 which is guided in its up and down movement by a suitable vertical guide rail 18 suitably rigidly mounted in the elevator shaft. A similar guide rail (not shown) is mounted on the opposite side of the elevator shaft.

Each assembly 12 and 14 comprises levers 20 and 22 which have a scissor-like movement by being pivotally connected together substantially at their centers by means of pivot pins 21 and at their ends by pivot pins 23. The upper ends of each assembly terminate in levers 25 which are each half as long as levers 20, 22 and extend from 2,975,868 Patented Mar. 21, 1961 end pivots 23 to a mutual pivot pin 26 that is rigid with the elevator cage as shown in Figure 2. As shown in Figure 2 each pin 26 carries just outwardly of the frames 12 and 14 a rectangular vertically elongated guide shoe 27 adapted to slidably fit within guide channel 28 of the associated guide rail 18. Since the outer surfaces of shoes 27 essentially bottom in the channels 28, this prevents sidewise shift of the elevator cage during operation, and the elongated shoes restrain tilting of cage 16 about axes 26.

The lower levers 20, 22 of each pair have a special pivot unit 29 that comprises coaxial pins 31 projecting outwardly therefrom to journal the respective levers as shown in Figure 3. Several of the pins 21 may be modified to mount guide shoes like 2'7 to travel up and down channel 28 for added stability.

Laterally aligned rotatable threaded vertical shafts 31 on which units 29 are threadedly mounted like nuts extend up the sides of the elevator shaft and may have upper end journal supports shown at 31a. The lower lever 20 by reason of the location of nut unit 29 is slightly inwardly displaced from the vertical plane of the other levers 20 of its frame but this is not substantial.

The lower end of each shaft 31 has fixed thereto a bevel gear 32 that meshes with a bevel gear 33 on the associated end of a cross shaft 34. The lower ends of lowermost levers 2t] and 22 are pivotally connected to oppositely projecting pins 35 rigid with travelling collars 36 threadedly mounted on rotatable parallel shafts 37, one journalled on each side of the elevator shaft floor as on posts 38. The ends of shafts 37 are oppositely threaded so that collars 36 move together or apart when the shaft 37 is rotated.

Each collar '36 has an axle 39 projecting oppositely from pin 35 to journal a supporting wheel 41 that may run on the fiat floor of the elevator shaft at 42 or in suitable guide tracks as at 43.

Each shaft 37 has rigid therewith a worm wheel 44 meshed with a worm 45 on the end of a cross shaft 46 that is journalled on suitable supports in the elevator shaft in parallel spaced relation with respect to cross shaft 34. A reversible electric motor 47 drives the input shaft 48 of a conventional bevel gear type differential gear mechanism 49 having oppositely outwardly projecting output shafts 51 and 52 that are differentially driven in the same direction. Shaft 51 has fixed to it a spur gear 53 meshed with a spur gear 54 on shaft 46, and shaft 52 has fixed to it a spur gear 55 meshed with spur gear 56 fixed on shaft 34. Thus when motor 47 is actuated to drive shaft 48 in either direction, side shafts 37 are similarly driven simultaneously, and vertical shafts 31 are similarly driven simultaneously, but the shafts 37 are driven differentially with respect to shafts 31.

The relative directions of drive and the gear and thread sizes are such that when shaft 48 is driven in one direction shafts 31 will be driven so as to raise units 29 thereby tending to expand the frames 12 and 14 vertical ly upwardly, and at the same time the collars 36 on the respective shafts 37 are shifted toward each other, further tending to expand the mechanism frames 12 and 14 upwardly. In this manner since the shafts 31, 31 and 37, 37 are differentially driven all of the forces tending to upwardly raise the elevator cage are evenly balanced and distributed. The frames 12 and 14 vertically support opposite sides of the platform at lo'and they are sufficiently strong to be self-supporting and non-buckling laterally under the weight of the platform.

Through use of this novel differential drive arrangement, a uniform actuating force is applied at all essential points which provides the scissor-like movement of lower terminating levers 20 and 22 necessary to expand and contract frames 12 and 14. It will be appreciated that the units 29 connecting lower terminating levers 20 and 22 will move up and down at a different rate than that which the collars 36 will move toward and away from each other respectively. This difference in rates of movement is compensated for by the differential drive action so that a smooth and even actuating force is applied at all points of movement of the assemblies during expansion and contraction thereof, resulting in smooth rapid elevator actuation. e The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. a

What is claimed and desired to be secured by United States Letters Patent is:

l. In an elevator assembly, a load carrying platform,

two vertically expansible and contractible mechanism frames operatively connected to opposite sides of said platform, each of said frames comprising a plurality of pivotally connected levers, means for applying a direct lifting or raising force to at least one point in each frame where the levers are pivotally connected, means for applying opposite forces for moving together or apart the ends of at least two of the pivotally connected levers, said latter forces being applied in directions at right angles to said first named force but also tending to raise or lower said platform, and means for differentially driving said force applying means.

2. An elevator comprising a pair of spaced expansible and contractible mechanism frames each made from a series of pivotally connected levers, load carrying means mounted on the upper ends of said frames, the lower end of said frames terminating in crossed levers having mutual pivot points between their ends and lower ends movable toward and away from each other, internally threaded members pivoted on said lower ends of each of said terminating levers and threaded in opposite directions from each other, horizontal rotatable shafts each having oppositely threaded ends within said members, two further internally threaded members each carrying the pivot point between the ends or" said lower levers of each frame, a vertical rotatable shaft threaded in each of the further threaded members, and differential drive means having one power output operatively connected to said horizontal shafts and another power output operatively connected to said vertical shafts, said difierential drive means being operative to simultaneously uniformly expand or contract said frames depending upon the direction in which said differential means is driven.

3. In an elevator, a load carrying platform, spaced expansible and contractible mechanism frames each comprising a series of pivotally connected levers and said frames being operatively connected at their upper ends to said platform, lower terminating levers on each of said frames having means pivotally connecting them to each other intermediate their ends and their outer ends a 4 being movable toward and away from each other substantially in a horizontal plane, said pivot connections of said lower levers being movable up and down substantially in parallel vertical lines, differential drive means for said frames, a first power output for said differential drive means comprising rotatable shaft and gear means operatively connected to said terminating lever ends for moving them in directions toward and away from each other, respectively, and another power output for said differential drive means comprising rotatable shaft and gear means operably connected to said pivot connections of said lower levers, said pivot connections of said lower levers being movable upwardly only when said lever ends are moved toward each other and downwardly only when said lever ends are moved away from each other.

4. In the elevator defined in claim 3, the outer ends of said lower levers being supported on rollers to facilitate movement of the ends of the levers toward and away from each other.

5. In the elevator defined in claim 3, means pivotally connecting said lower levers together in each frame'being a member having a pair of pivot pins extending in opposite directions from its longitudinal axis and on which said lower levers are pivoted, and vertical power screws threaded in said members and driven from said other power output.

6. In an elevator, a pair of spaced expansible and contractible mechanism frames each made from a series of pivotally connected levers, load carrying means mounted on the upper ends of said frames, the lower ends of each of said frames terminating in two crossed levers pivoted at a point between their ends and with their outer ends movable toward and away from each other, supporting pivot members mounted on the lower ends of said crossed levers, said members being threaded oppositely, horizontal rotatable shafts suitably threaded at opposite ends in said members, vertically movable units mounted at and carrying the vertical rotatable shafts threaded in said units, two cross shafts, one of said cross shafts being geared at opposite ends to said horizontal shafts, and the other of said cross shafts being geared at opposite ends to said'vertical shafts, and differential drive means having power outputs differentially driving said cross shafts.

7. In an elevator, a load-carrying platform, spaced vertically expansible and contractible mechanism frames supporting opposite sides of said platform and each comprising a.vertical series of pivotally connected crossed levers, actuating means for said frames comprising a first drive system operably connected to vertically displaced corresponding lever pivot points of each of said mechanism frames, a second drive system operably connected to levers at each side for horizontally displacing portions thereof, and reversible means for differentially and simultaneously driving said systems in synchronism and in such directions as to expand or contract said frames to raise or lower said platform.

References Cited in the file of this patent UNITED STATES PATENTS 956,189 Schwartz Apr. 26, 1910 1,365,252 Langill Jan. 11, 1 921 1,545,223 Westrate July 7, 1925 

